The examples given with base 10 and 2 in the question are positional bases. In a positional base 1, you only got one digit, with no value: 0. All positions will have zero value, and you can only represent one number: 0. – Bijective base 1 would be one way to make it funcitonal, but that isn’t a positional base.
https://math.stackexchange.com/questions/371972/what-would-base-1-be